Global Warming and Allergic Diseases

Impact of Global Warming and Climate Change in Allergic Diseases

“Global warming”, also referred to as “climate change”, is a subject that has received major attention during the past years. Climate change refers to alterations in weather conditions over extended periods, often decades, centuries, or millennia. The concept of global warming popularly used now refers to a gradual raise in the global ambient temperature that began in the 19th century, parallel with an increase in levels of air pollutants resulting from human activities, associated with industrialization and the use of fossil fuels (“anthropogenic emissions”). These air pollutants are various, with carbon dioxide being the most representative of them.

The Intergovernmental Panel on Climate Change (IPCC) is a group comprised of thousands of scientists from multiple countries with the mission of investigating the global warming phenomenon. The IPCC has prepared extensive reports, which review data regarding the topic, and support that global warming is a real phenomenon.

Global warming and climate change affect the prevalence and severity of allergy and asthma, particularly due to changes in patterns of outdoor aeroallergens by increasing temperatures and amounts of carbon dioxide in the atmosphere. Pollen seasons last longer, plants produce greater quantities of pollen, and pollen has increased allergenicity.

The effect of climate change and global warming on allergenic fungi is less noticeable than the effect on pollen, and it is mainly supported by indirect evidence. However, changes in rainfall patterns and catastrophic flooding events are becoming more common. Microbial growth secondary to flooding, particularly fungal growth (“mold”) affects the respiratory health of exposed individuals. It has been suggested that allergic individuals could suffer more severe and frequent exacerbations of the disease in the future.

Global warming and climate change could indirectly be responsible for a switch of the fungal species that grow indoors, with selective allergenicity. Particular attention should be given to these fungal genera and species, as people might become sensitized to them. This aspect should be considered when proposing changes in diagnostic testing and immunotherapy in order to adapt to climate change. The excessive number of fungal allergenic extracts available on the market should be reduced, and allergen manufacturing companies should focus on obtaining clinically relevant fungal extracts.

Pollen versus spores

The Relevance of Pollen and Fungal Spores in Allergic Diseases

Pollen and fungal spores are associated with seasonal and perennial allergies. However, most scientific literature thus far suggests that pollen allergy is more clinically relevant than fungal allergy. Several environmental and biological factors and the difficulty in producing reliable fungal extracts account for this. Biodiversity, taxonomy, and meteorology are responsible for the types and levels of pollen and fungal spores, their fragments, and the presence of free airborne allergens. Therefore, it is difficult to accurately measure both pollen and fungal allergen exposure.  In addition, understanding the enzymatic nature of fungal and some pollen allergens, the presence of allergenic and non-allergenic substances that may modulate the allergic immune response, and allergen cross-reactivity, are all necessary to appropriately evaluate both sensitivity and exposure to pollen and fungal spores.. The raw materials and manufacturing processes used to prepare pollen versus fungal extracts differ, further increasing the complexity to properly determine allergic sensitivity and degrees of exposure to pollen and fungal spores.  The pollen extracts used for diagnosis and treatment are relatively consistent, and some have been standardized. However, obtaining clinically relevant fungal extracts is more difficult. Doing so will allow for the proper selection of such extracts to more appropriately diagnose and treat both pollen- and fungal-induced allergic diseases.

Pollen versus spores